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Re: RFC -- update_equiv_regs and friends
- To: "John David Anglin" <dave at hiauly1 dot hia dot nrc dot ca>
- Subject: Re: RFC -- update_equiv_regs and friends
- From: Jeffrey A Law <law at redhat dot com>
- Date: Thu, 08 Mar 2001 16:50:47 -0700
- cc: john at feith dot com, gcc at gcc dot gnu dot org
- Reply-To: law at redhat dot com
In message <200103061616.LAA15507@hiauly1.hia.nrc.ca>you write:
> > In message <200103041901.OAA05842@jwlab.FEITH.COM>you write:
> > Note that rtx_varies_p does check that the address is non-varying too:
> >
> > case MEM:
> > return ! RTX_UNCHANGING_P (x) || rtx_varies_p (XEXP (x, 0), for_ali
> as);
>
> On the PA, pic refs are unchanging so the address check doesn't come into
> play.
Huh?
If RTX_UNCHANGING_P is set on the MEM (like it is for a PIC reference on the
PA), then we will call rtx_varies_p on the address (note carefully the "!"
before RTX_UNCHANGING_P). If RTX_UNCHANGING_P is not set, then rtx_varies_p
will return nonzero because we don't know if the memory location is changes
or not.
jeff